The $250 to $300 for a single bird will be less that additional feed, penning space, and time (years) needed to realize stated goal. Approach you are laying out will require making a lot more birds where the overwhelming majority will not take you in the desired direction.My goal result from this project is to make a sporty type bird with less of the fighting instinct, making them easier to control pretty much.
I'm planning to be chicken breeder, & this just makes it a good way to practice. And my budget isn't great either. I can't just spend $250 -$300 dollars on a particular breed either. I wish I could though.